Refrigeration



Aug. 31, '1943. c. c. COONS ETAL 2,328,196

REFRIGERATION Filed April 2, 1941 2 Sheets-Sheet 1 INVENTORS Curtis 6'. 6'0 0128 BY William E Kiilo ATTORNEY C. C. COONS ET AL.

. Aug. 31 1943.

REFRIGERATION Filed April 2, 1941 2 Sheets-Sheet 2 ATTORNEY INVENTORS Curtis 6. Coons y William HKitto in the food storage compartment,

Patented Aug. 31,1943

OFFICE 1 REFRIGERATION v 7 Curtis 0. Coons, North Canton, and William H.

Kitto, Canton,

Ohio, asaignors to The Hoover (lfirlnpany, North Canton, hio, a corporation of 0 o Application April 2, 1941, Serial No. 386,395 In Great Britain A ust 20, 1937 v 38 Claims, (CL. 62-1195) This invention relates to refrigerating systems and more particularly to evaporator structures for such systems.

This application is a continuation-in-part of our application Serial No. 220,189, filed July th, 1938 and now abandoned.

In the past the evaporators of three-fluid absorption refrigerating systems have been of the type in which the liquid refrigerant flows downwardly therethrough by gravity. Because of this condition the condenser supplying liquid to the top portion of the evaporator must extend thereabove. Due to the rigid space limitations of domestic refrigerating cabinets, it is necessary to extend the condenser above the refrigerating cabinet thus producing an upsightly construe or to position the evaporator at a low level a large quantity of space available in the storage compartment and causing the evaporator to operate under inefilcient conditions. Condenserevaporator structures have been devised in which the condenser extends to a level below the top of the evaporator but these structures either require a complex and costly condenser-evaporator construction or they require a pumping device in the liquid line between the condenser and the 1 evaporator.

We have discovered an entirely new principle of evaporation whereby the bottom portions of the condenser and evaporator may be substantially at, the same level and all without the provision of complex condenser evaporator structures or separate liquid elevating devices. We have discovered that a stream of pressure equalizing medium travelling at a high velocity through the evaporator will drag or sweep the liquid refrigerant upwardly through the evaporator under very turbulent conditions while the liquid is evaporating into the pressure equalizing medium.- Our condenser may consist of a simple finned coil connected to the bottom of the evaporator which may be simply a rising conduit connected to a' source of pressure equalizing medi We have devised a system in which theevaporator functions simultaneously as an evaporator ating system propelled stream of inert gas is self-regulating for atmospheric temperature changes. That is,.thesystem automatically regulates itself to compenthus wasting to the rate of flow of the pressure equalizing medium. a

We have further discovered that a refrigerembodying an evaporator in which the liquid is dragged or swept therethrough'by a sate for internal changesinduced by variations in atmospheric renders unnecessary the complex and expensive auxiliary equipment previously used to accomplish this result. a

An evaporator in which the liquid refrigerant is dragged or swept therethrough by apropelled stream of inert gas is well adapted to multi-temperature operation. An evaporator of thistype inherently produces refrigeration at several temperatures whereby it is readily adapted to installations requiring a structure in which a portion is designed to be operated at low temperatures for freezing purpose and another portion is designed to be operated at high temperatures for box-cooling purposes.

machines have a number of inherent characteristics rendering the construction of the evapora-' perse, as an elevating device for the liquid refrig-' erant supplied thereto, and as a means for regulating the productionof refrigeration. Due to the fact that the liquid refrigerant is caused to flow through the evaporator solely by the pressure equalizing medium passing therethrough, it follows that, the quantity of refrigeration produced at any given time is directly proportional the freezing of ice dimcult. these is the fact that the evaporator must be soconstructed and arranged that the liquid refrigerant flows continuously downwardly there-' through by gravity. This necessitates the use of evaporator conduits having a continuous slope.

Consequently the evaporator conduits are. not.

placed directly beneath the ice freezing trays; as such trays must be supported in a level position.

Due to the inherent limitations of previous systems, previous evaporators consist of very heavy cored castings having continuouslysloped passageways in the sides thereof. This provides the necessary flow of the liquid refrigerant but it requires a heavy cast evaporator casing in which.

the actual gas and liquid passes are rather remote from the tray, are on the side walls of the evaporator where they are in most effective heat conductingrelationship with the air in the stor-{ age cabinet and are unsightly. This super-cools the air in the storage compartment and causes excessive driving of foodstuffs stored therein and excessive frost deposit on-the evaporator. great a proportion of therefrigerating eflect is directed into the storage compartment and an insufficient portion is available forice freezing because of the large heat now resistance in the temperature conditions. This absorption refrigerating Prominent among bar.

path provided between the bottom of the freezing tray and the actual gas and liquid contact conduit. The result is unduly slow ice produc-- tion and a low' efflciency.

In previous constructions various parts of the conduits are connected by risers on the side of the evaporator casing and the conduits on the two sides of the casing are connected by passageways formed in the evaporator casing and extending along the back thereof. These also are fully exposed to the air in the cabinet and are thermally remote from the ice freezing trays.

In prior constructions the amount of coil which can be arranged in a restricted vertical plane is limited as it is not feasible to extend the verti-' cal dimension of the evaporator because this would render a large part of the storage chamber useless. Another limiting factor in prior con-- structions arises from the fact that heat must be conducted from the bottom of the freezing tray laterally through the tray supporting shelf to the side walls of the evaporator. This precludes an evaporator construction in which more than one ice tray is positioned at any given vertical elevation; that is, ice trays cannot be positioned side by side. I

It is accordingly an object of the present invention to provide a three-fluid absorption refrigerating machine in which the evaporator conduits may lie in a horizontal planedirectly beneath and in supporting relationship with the ice trays and out of heat contact with the exterior walls of the ice freezing chamber.

It is a further object of the invention to provide an evaporator for a refrigerating machine of the character described so constructed and arranged that the conduits connecting adjacent vertically spaced coil sections are positioned within the ice freezing chamber ina position to be out of'the way of the ice trays and out of direct heat transfer relationship with the side walls of the ice freezing chamber.

It is a further object of the invention to pro-' vide an evaporator in which the evaporator conduitsmay lie entirely in a horizontal plane so as directlyto support the ice trays.

It is a. further object of the invention to provide an evaporator which may be embodied in 'a three-fluid absorption refrigerating machine without necessitating the use of heavy castings and without necessitating a construction in which the principal refrigerating effect is transmitted directly to the side walls of the ice freezing charm-- It is anotherobject of the invention to provide an evaporator for three-fluid absorption refrigerating systems in which the length of the system. I

evaporatorpassagewaymay be as great as desired, the evaporator passageway may be -ar-" ranged. in direct heat conducting relationship with the ice trays, there is no. need to make the vertical dimensions of the evaporator excessive, and a plurality of ice trays may be positioned side by side at the same elevation without impairing theefilciency of the apparatus or increasing the time required to freeze ice. v

It is another object of the. invention to provide an evaporator for three-fluid absorption refrigerating machines in which the actual evaporator conduits are concealed and are so positioned that the evaporator may be styled as desired.

It is a further object of the present invention to provide an evaporator-construction in which a single evaporator element produces refrigeraa higher temperature for air cooling and in which the ice freezing and air cooling loads on the system are separately borne by-distinctparts of a single evaporator operating at distinct tempera- This time lag is due to the interval required between application of heat to the boiler and generation of refrigerant vapor therein. Our evaporator, overcomes this diiiiculty by'storing therein a quantity of liquid refrigerant immediately the control mechanism de-energizes the system in response to the condition for which the control a mechanism is set. The refrigerant so stored produces refrigeration immediately the control mechanism re-energizesthe system and carries the system load until such time as the boiler shall have come into full operation.

Heretofore it has been considered necessary to provide the evaporators of refrigerating systems with a draining device to remove therefrom foreign bodies which are carried by various fluids circulating through the evaporator.

These foreign bodies customarily were removed through a drain connected to the bottom of the evaporator, but the drain had th great; disadvantage that it was apt to become clogged and permitted liquid refrigerant to by-pass to the other parts of the system.

Accordingly it is another object of the present invention to provide an absorption refrigerating system which is drainless, that is, a system in which foreign matter such as absorption solution, anti-corrosion material and scale are removed from the top of the evaporator through conduits forming a part of a fluid circuit of the It is another object of the invention to provide a refrigerating system in which the foreign material reaches its greatest concentration relative to the refrigerant liquid in the upper, box-cooling, part of the evaporator where it is desirable that refrigeration be produced at relatively high temperatures. Wherefore the dilution of the refrigerant in the inert gas does affect the production of refrigeration adversely and the liquid refrigerant in the lower, low temperature. p rts of the evaporator is not diluted by foreign material to an extent suflicient to interfere with the operation of the machine.

- It is another object of the invention to provide an absorption refrigerating apparatu in which a body of refrigerant liquid is maintained in the evaporator, the inert gas is bubbled through the body of liquid and foreign material finding its way into the evaporator is removed from theupper portion of the evaporator substantially continuously and at a rate sumcient to prevent'accumulation of foreign material in the body of liquid.

Other objects and advantages of the invention will become apparent as the description proceeds when taken in connection with the accompanying drawings, in which:

Figure 1 is a diagrammatic illustration of a three-fluid absorption refrigerating system having' the evaporator thereof shown in perspective and on an enlarged scale.

Figure 2 is a detail view on an enlarged sca taken on the line Z--2 of Figure 1.

Figure 3 is a side elevational 'view in section.

showing the upper portion of a domestic refrigerator cabinet embodying the present invention.

Figure 4 is a front elevational sectional view of the device illustrated in Figure 3.

Referring now to the drawing in detail and first to Figures 1 and 2 thereof, it; will be seen that we have illustrated our invention as applied to a three-fluid absorption refrigerating system comprising a boiler B, an analyzer D, a rectifier R, an air-cooled condenser C, an evaporator E, an air-cooledabsorber A, and a pressure equalmedium circulating fan F driven by an electrical motor G. With the exception of the evaporator E, all elements of this system are illustrated diagrammatically, it being understood that they may be of any specific construction or form desired.

The elements Just described are suitably connected by various conduits to form a complete refrigerating system including a plurality of gas and liquid circuits. It will be understood that the system is suitably charged with a refrigerant, such as ammonia, an absorbent, such as water, and a pressure equalizing mediunnpreferably a dense inert gas such as nitrogen.

The boiler B is heated in any suitable manner as by a gas burner or an electric cartridge heater. The boiler B and electrical motor G are controlled in any suitable or approved manner. A suitable control mechanism indicated generally at 18, Fig. 3, is disclosed in United States Patent No. 2,228,343. A

Application of heat to the boiler B vaporizes refrigerant from the solution therein contained. The vapor so generated passes upwardly through the analyzer D in counterflow to strong liquor flowing downwardly through the analyzer whereby the refrigerant vapor is of entrained absorption fluid and further vapor is generated by the heat of condensation of the absorption liquid. The refrigerant vapor is conveyed from the analyzer D to the condenser C by way of a conduit The conduit includes an air-cooled rectifier R which condenses any vapor of absorption solution which may pass through the analyzer D. The refrigerant vapor is liquefied preferably by heat exchange surrounding air ,in the condenser C which extends substantially to the level of the bottom of the evaporator. Refrigerant liquid is discharged from the condenser C through a conduit |2 into the evaporator E.

The exact operation of the evaporator will be explained in detail hereinafter. For the present it is suflicient' to note that the liquid refrigerant supplied to the evaporator E evaporates into a substantially freed,

The weak solution formed in the boiler by the generation of refrigerant vapor is conveyed therefrom to the upper end of the absorber A through a conduit 2a which in part forms the inner member of a liquid heat exchanger 2|. The weak absorption solution flows downwardly through, the absorber A in counterflow to the inert gas refrigerant Vapor mixture as previously described. Strong absorption solution formed in the absorber A flows to duit H from which it is drained by a conduit 22 into a strong solution reservoir 23. The strong solution is conveyed from the reservoir 23 to the liquid heat exchanger 2| by a conduit 24. A

uid heat exchanger analyzer D.

The absorber A is at an elevation higher than the liquid level in the boiler analyzer system 'B-D; therefore, it is necessary to include an elevating device in the weak liquor line 20 connecting the boiler B and the top of the absorber A. For this purpose a bleed off conduit 21 is connected between the gas discharge conduit l1 and the weak liquor line 20 below the liquid level in the boiler-analyzer system whereby the weak liquor is absorber A by gas-lift action.

Referring now to the evaporator E in detail, it will be seen that it comprises a coil section 30 constituting a low temperature or ice-freezing portion and a high temperature or box-cooling section |3 which is providedwith a plurality of air-cooling fins 3|. The box-cooling conduit I3 is considerably larger in diameter than the con'-. duit fo'rmingthe coil section 30. i

In the embodiment illustrated, the coil section 30 of our evaporator comprises a plurality of vertically spaced parallel horizontal coil sections 32, 33 and 34. The coil sections 32 and 33 each comprise four spaced parallel conduit elements.

The outer conduits 35 and 36 are serially conpropelled stream of inert gas to produce refrigoration. Themixture of inert gas and refrigerant vapor formed in the evaporator E is discharged from the box-cooling section 3 thereof into the inner conduit ll of a gas heat exchanger l5. The conduit l4 communicates with the lower end of a tubular air-cooled absorb-er A.

The inert gas refrigerant vapor mixture passes upwardly through the absorber A in counterfiow to absorption solution flowing downwardly therethrough whereby the refrigerant vapor is separated from the inert gas by absorption. The purified inert gas is discharged from the absorber into the outer path of II from which it is rethrough a conduit i8,

inner conduit 31 of section 34 nected'by a conduit 29 extending across the rear of the evaporator. The inner conduits 3'! and 38 are connected at the front to the outer conduits 35 and 36,respectively. The inner conduits form the inlet and outlet connections of each coil section.

The gas inlet conduit I8 is connected to the the lowest coil section 32 which in turn is connected by a riser conduit 39 to the intermediate coil section 33. The intermediate coil section 33 is connected by a riser conduit 40 to the top coil section 34. The top coil is identical with the coil and 33 except that it does not have an inner conduit corresponding to the inner conduit 38 of the coil sections 32 and 33. a

The outer conduit 35 of the upper coil section is connected to the front end of'the box-cooling conduit 3 by a riser conduit; 4|. The liquid refrigerant supply line |2 opens into the gas inlet conduit 8 slightly above the plane of the lowest coil section 32.

A drain conduit 42, which is smaller in diameter than the conduits of the ice-freezing evaporator section 30, ls connected into the conduit element 38 of the coil section 32' adjacent the riser conduit 33 and to the strong solution return line 24. The conduit 42 is connected into the top portion of the conduit 38 whereby it will not completely drain the coil section 32. t

It is apparent from the description above that our evaporator comprises a plurality of horizontal freezing sections connected by riser conduits the low point of the conelevated to the top of the sections 32 which will house the. generator, liquid heat exchanger, absorber and connecting conduits.

The apparatus includes an insulated cabinet 50 provided with an insulated closure 5| to provide access to the storage compartment 52. The evaporator E described in connection with Figure .1 is positioned in the top central portion of the compartment 52 and is associated with a freezing chamber 53 which encloses all portions of the evaporator with the exception of the upper air cooling element l3 and its associated fins.

The horizontal evaporator coil sections 32 and 33 underlie and support ice tray receiving shelves 58 and 59, respectively. The shelves 58 and 59 are constructed preferably of light weight sheet material having a high heat conductivity. The shelves 58 and 59 may be attached to the coil sections 32 and 33 in any suitable manner as bywelding, brazing, soldering or by mechanical clasps or the like. The front and side edges 60 of the plates 58 and 59 are turned downwardly in order to surround the front and side edges of the coil sections 32 and 33, respectively. The rear edges of the plates 59 and Eli are turned up as is indicated at Si in order to form arear stop for the ice trays 65.

.The casing element 53 includes top, bottom, rear and side walls which may be made integrally or of separate sections secured together as may be desired. As illustrated, these walls are in one piece.

The casing 53 is supported from the shelves 5B and 59 and is spaced in non-heat conducting relationship thereto. This is accomplished by attaching the side walls 10 of the casing as to the side flanges of the plates 58 and 59. Suitable rivets H which may be of insulating material, if desired, secure the flanges to the side walls 10 of the casing 53. Direct heat trans,-

' fel between the plates 58 and 5a and the casing 53 is prevented by insulating spacers 32 which surround the rivets and space the flanges 50 from the walls 10. As a consequence of this construction no direct heat transfer path between the walls ill and the plates 58 and 59 is provided.

The upper coil section 34 of the evaporator, as may be seen from Figures 3 and 4, is positioned in spaced relationship with the top wall of the casing 53 and the lowest coil section32 "is positioned in spacedrelationship with the bottom wall of the casing 53. Consequently, the evaporator is at no point in direct heat conducting relationship with the casing 53.

The riser connections 39 and 40 of the evaporator are within the casing 53 in the rear portion thereof behind the upturned ice tray stop flanges 6i but they are not in direct heat conducting relationship with the rear wall of the casing 53. The conduit 4! which connects the coil sections 36 to the air cooling evaporator section i3 passes upwardly through the upper wall of the casing 53 and the evaporator section 93 andits associated fins 3| are positioned in spaced relationship with the top wall of the casing 53.

A suitable closure element 75 is hingedly mounted along one edge to the casing 53 in order front. e plate 16 also carries the control knob 11 which connects to the control mechanism 18 through a shaft 19 passing in part through the fins 3!.

A shelf is mounted in the compartment 52 beneath the evaporator and is provided with a depressed portion 8| which serves as-a seat for a drip tray 82. a

The evaporator is inserted into the chamber 52 from the rear of the cabinet through an opening 82 which is closed by a suitable insulated closure plate 83 and a sealing gasket 84.

The gas heat exchanger i5 is partly embedded in the closure element 83 and in the rear wall of, the insulated cabinet 53, and the gas connections between the evaporator and gas heat exchanger pass into the closure element 83.

The rear wall of the cabinet is provided with an air-cooling duct 86. The condenser C is positioned in the upper portion of the air cooling duct 88 and the condenser-evaporator connection 82 passes through the closure element 83. The drain conduit 42 also passes through the element 83. I

The control mechanism, which is indicated diagrammatically at I8, may be mounted upon the rear face of the closure element 83 and connected by suitable conduits and electrical conducthe boiler.

When the refrigerating mechanism is ener-- gized'a propelled stream of inert gas will be supplied to the evaporator through the conduit I8 and liquid refrigerant will be supplied to the conduit Hi from the condenser C. The liquid refrigerant will be swept through'the lowest coil section 32 by the inert gas, up the riser conduit 39, through the central coil section 33, up the riser conduit 40, through the top coil section 34, and through the riser conduit dl into the boxcooling conduit E3. The liquid refrigerant collects in the riser conduits 39, 40 and d! and forms liquid columns therein through which the inert gas bubbles or blasts its way carrying portions of the liquid column therewith into the next higher evaporator section.

The liquid refrigerant progressively evaporates into the inert gas stream as it is being elevated thereby through the evaporator. In normal oporation, only sumcient liquid refrigerant is supplied to produce the necessaryquantit of refrigeration, but any liquid which may not be evaporated in the box-cooling conduit flows into the gas heat exchanger and is carried through the gas conduit system into the bottom of the ab .liquid refrigerant supplied to the evaporator per unit of time. Consequently, the velocity of flow of the inert gas through the evaporator will be materially greater than the velocity of flow of I the condenser system.

the liquid refriferant. This evaporator meets that condition ideally while circulating the liquid refrigerant upwardly through all portions of the evaporator.

Several factors have a material bearin on the design of an apparatus which will produce the desired conditions. The lifting power of the inert gas stream is a function of its density, pressure and velocity of flow through the evaporator. In general, an increase in the value of any one or more of the above enumerated factors results in an increase in the lifting power of the inert gas.

Other things being equal, the velocity of the inert gas will be a function of the effective cross-sectional area of its path of flow; an increase in. the effective cross-sectional area of that a decrease in gas velocity. has been found that a propelled stream of nitrogen will circulate liquid ammonia upwardly through an evaporator constructed of approximately one-half inch inside diameter tubing of approximately ten inches, a pressure differential of between two and four inches of water between the gas inlet and outlet connections to the evaporator, and with the total system pressure ranging between 270 and 400 pounds per square inch. The above dimensions are cited by way of example only and are not limitin in any sense.

The drain conduit 42 is normally inactive but it performs an important function under certain conditions. If, for any reason, the circulating motor G fails to start when the control mechanism energizes the system, liquid refrigerant will discharge into the coil section 32 and tend to block it. If the coil section were blocked, the fan, when started, might inert gas stream through the system and refrigeration could not be produced. The drain conduit 42 prevents blockage of the coil section 32- while at the same time it is so placed that it does not completely drain the coil section 32.

The placing of the drain conduit 42 is highly important for the following reason. During the normaloperation of the system there is a considerable quantity of liquid refrigerantbeing carried upwardly through the evaporator and there is also a certain amount of liquid refrigerant in When the control mechanism de-energizes the circulating fan, the liquid refrigerant contained in the condenser and in erant.

Blockage of the coil section 32 may also occur in another manner. In mamffacturing, handling and installation of the apparatus it may be tipped sufllciently, or even upended, so as to cause the absorption solution to flow into and become trapped in the evaporator. If this occurs the drain 42 will simply return this liquid to the absorption solution circuit except for the quantity trapped in coil 32 below the level at which conduit 42 is connected. Theliquid trapped in coil and having a vertical heightevaporator. This liquid,

be unable to force the of the evaporator at tion circuit.

During normal operation drain 42 is non-func-- tional as the apparatus will be designed and charged to prevent wastage of liquid refrigerant through drain 42. Drain 42 is merely a safety device to prevent blockage of the evaporator due to'failure of the gas circulator or 'to treatment of the system which will cause the evaporatorto become filled with absorption solution.-

In the normal operation of absorption refrigerating'machines some absorption solution vapor reaches the condenser, and perhaps the evaporator, and appears in the liquid state in the as well as any-other stray foreign material finding its way into the evaporator, such as lubricant, anti-corrosion material and scale, must be removed from the evaporator. Prior practice has been to remove such material through a small separate drain mechanism, connected to the bottom of the evaporator, which added to the cost and complexity of the system and sometimes interfered with normal operation thereof.

The small diameter conduit of which these drains were made also rendered them liable tobecorne clogged with scale. In the present construction such foreign material simply circulates upwardly throughthe evaporator under the impetus of inert gas and is removed from the top of the evaporator through a normal part of the system, the inert gas circuit, to the absorption solution circuit. Thus, considered as a functional entity, the evaporator consists of a continuous unbroken drainless conduit through which the inert gas, liquid refrigerant and foreign material circulates and is purged from the top thereof through the inert gas circuit. The drain 42 does not relieve the evaporator of foreign material in normal operation. In normal operation conduit tents and purposes.

conduits is large compared to the customary conduit; consequently there is no danger of clogging and trapping of foreign material in the present evaporator construction.

It is important that the foreign matter be removed from' the top of the evaporator. In prior construction this material collects in the bottom a point at which the quantity of liquid refrigerant is small. Consequently the dilution of the refrigerant liquid is a real disadvantage because of the fact that very low temperatures are desirable in the bottom of the evaporator but the relatively large dilution of the occurs in the top of the evaporator where relatively high temperatures .are desirable. In the present construction bodies of liquid are maintained in the evaporator, for example, in the rising conduits 39 and 40, as explained hereinafter, and the inert gas bubbles through such bodies of liquid. Nevertheless the refrigerant liquid bodies of liquid does not decrease due to progressive accumulation of foreign material because the foreign material is continuously removed therefrom and is conveyed away from the evaporator above such bodies of the liquid.

42 is non-existent to all ingas 7 conditions.

- refrigerating eflect.

It is to be noted that the leanest gas is supplied to the lowest portion of the evaporator and that the vapor pressure of the ammonia in the gas stream progressively increases from the bottom to the top portion of the evaporator. This phenomenon insures that the box-cooling coil l3'will not operate at temperatures sufliciently lowto collect large quantities of condensed moisture or frost.

The bodies of liquid present in the various parts of the evaporator coils and particularly in the riser conduits have a marked throttling effect on the inert gas stream: furthermore, this throttling effect is more noticeable at low pres- ;sures than at high pressures. Thisfaetor makes the system self-regulating for external atmos-' pheric temperature conditions fortlie following reasons: A rise in atmospheric temperature de- I creases the efflciency of the absorber whereby the ammonia vapor pressure of the inert gas stream discharge from the absorber increases;

this means that a given quantity of inert gas is now able to pick up a lesser quantity of 'ammonia vapor thereby decreasing the amount of 'refrigeration available. But an increase in the temperature of the atmosphere causes an appreciable increase in the pressure of the fluids in the system. This increases the density of the in the pressure equalizing medium circuit. As the density of the pressure equalizing medium increases, the circulating fan causes it to be placed under a higher pressure and to circulate at a higher velocity. Therefore, an increase in the temperature of the atmosphere decreases the efficiency of theabsorber but automatically causes a greater quantity of. inert gas to be circulated through the evaporator whereby. refrigerating capacity is maintained under all atmospheric The action of the inert gas on the liquid refrigerant may be briefly described as follows:

In substantially horizontal conduits the gas stream flows over a stream of liquid in the bottom portion of the conduit to which it imparts a propelling force by the frictional drag of the gas stream as it passes over theliquid. Additionally, the dragging action of the gas on the liquid serves'to agitate the liquid stream which improves the gas and liquid contact therebetween and aids the evaporating process. In the elevating or rising conduits, the gas stream supports a body of liquid in a divided state through which the gas continuously forces itself agitating such body of liquid and blowing or dragging a portion thereof into the next evaporator conduit.

Though the gas is described herein as travelling at a high velocity, this term is to be understood in a relative sense because the velocity of the gas will depend upon the conditions prevailing in the particular system as noted above; .for example, in the particular embodiment of the invention disclosed herein", the velocity of gas flow through the evaporator is of the order of a few-feet per second if a dense gas, such as nitrogen, is utilized.

Thus, the high velocity stream of denseinert gas serves to distribute the refrigerant liquid through the evaporator non-uniformly as the liquid is evaporating into the gas to prochlce a Consequently, insectigns of the evaporator conduit in which the quantity of liquid present" is relatively small, the gas stream flows across the liquid dress n the same in the direction ofgflow of the-gas stream independently of the pull of gravity, whereas in otbe sections of the evaporator conduit in which the quantity of liquid present is greater, the gas stream passes into and out of or bubbles through the evaporating liquid refrigerant and serves to,

A propel a portion of such liquid further along the i'evaporator conduit by the frictionaldragging 'action of the inert gas stream.

Though the liquid supply conduit I2 is shown as entering the gas conduit ill at a level above the level of the conduit 31, this connection is made at this level merely forthe purpose of shortening the conduit and because it is convenient to make a. right angle connection between the conduits l2 and I8 as may readily be seen from Figurev3. The liquid could just as well be supplied directly to a horizontal portion of the coil 86. g

It is characteristic of this invention that the liquid supplied to the bottom coil, for example, flows therealong in the form of a stream which may at times be discontinuous but which does not block the conduit. The gas is supplied to the evaporator above the level of the liquid since the liquid supplied to the conduit 18 simply flows to the bottom portion of the horizontal coil 32. Nevertheless, the liquid which is collected in the rising conduits, such as conduits 39 and 40, substantially fills those conduits and the inert gas passes through such collected bodies of liquid; that is, the inert gas is supplied'at a level above the level at .which liquid is. supplied and subsequently bubbles or passes into and out of the liquid refrigera'n The level at which the gas is supplied to the evaporator issubstantially independent of the being only necessary that the gas and liquid be brought into contact in a zone in which the gas is flowing with sufiicient velocity and pressure, as is explained above, to propel the liquid through the conduit. '1

The flow of inert gas through the evaporator is substantially continuous and steady though there is a pressure gradient from the inlet to the outlet portions thereof due to the throttling action of the liquid, particularly in rising conduits, on the gas stream. This insures substantially continuous uniform propulsion of liquid through the evaporator and continuous production of refrigeration'whenever the refrigerating mechanism is operating.

It is apparent fromFigures 3 and 4 that the condenser extends to a level well below the level of the upper portion of the evaporator and that the same need not extend above the upper wall of the cabinet in order to provide sufllcient condensing area. the manner in which the evaporator may be placed at the highest feasible point withinthe storage compartment 52 without necessitating a special condenser construction, without cramping the condenser and without the use of a condenser which extends above the upper wall of the cabinet 50.

It is readily apparent from Figures 3 and 4 that the liquid refrigerant entirely traverses the ice freezing section of the evaporator in direct heat conducting relationship with the ice freezing trays before. the same is supplied to the air cooling evaporator sections it. .This tends to produce the lowest temperature where low temperatures are needed and to produce a higher refrigerating temperature in the air cooling element and ate. point lwhere such higher cooling temperatures, are very desirable.

These figures also illustrate walls heat conducting and are insulated from the shelves 58 and I9.

This construction effectively prevents the casing 53 from reaching an obiectionably low temperature and from accumulating excessivedeposits of frost and from excessively drying foodstuffs in the chamber 52. This construction also promotes rapid and efllcient freezing of ice because the tray for water to be frozen is the element having the best heat conducting path with the evaporator conduit. It is also to be noted thatv the conduits are all either vertical or horizontal and that the'ice trays are in exactly horizontal position even though the same are resting directly upon the freezing coils.

Consequently, the inert gas and liquid refrigerant flow in the same direction'with the liquidfiowing under the propulsion of the gas in horizontal, planes parallel to the planes of the bottom walls of the ice tray and in direct heat transfer therewith and in a positionsuch that the gas and liquid do not refrigerate the walls of the freezing chamber. inert gas flow upwardly through the evaporator. Consequently, the lowest horizontal coil sections, those which directly refrigerate the ice trays, receive the liquid refrigerant and lean gas whereby a very large refrigerating capacity is available to produce ice. While we have illustrated and described but a single embodiment of our invention, it is to be understood that .it is capable of expression in many other constructional forms and variations without departing from the spirit of the invention or the scope of the appended claims.

We claim: V a l. Refrigerating apparatus comprising an evaporator, an absorber, a boiler. a condenser, means connecting said evaporator and said absorber to form therewith a pressure equalizing medium circuit, means connecting and said boiler to form therewith an absorption solution circuit, means connecting said boiler,

condenser and evaporator to form a liquid refrigerant supply means for said evaporator, said evaporator comprising a plurality of horizontal vertically spaced coil sections and a superposed box-cooling section, riser conduits connecting adjacent evaporator sections, power-driven means for circulating fluid through said pressure equalizingrnedium circuit, said circuit being connected to cause fluids to circulate upwardly through said evaporator, said condenser being connected to the lowest of said coil sections, and drain means connected between the top portion of the lowest of said evaporator. sections and said'absorption solution circuit.

2. That improvement in the art of absorption refrigeration which includes the'steps of propelling a pressure equalizing mediumthrough a circuit including evaporating and absorbing zones, supplying liquid refrigerant to saidevaporating zone, circulating liquid refrigerant upwardly through said evaporating zone by the drag exerted on the liquid by the propelled stream of pressure equalizing medium as the liquid is evaporating into said pressure equalizing medium to produce refrigeration, diverting a portion of the The liquid refrigerant and said absorber supplying the same rator of liquid pressure equalizing medium from the pressure utilizing the diabsorption solution into said absorbing zone by -gas lift action.

3. Absorption refrigerating apparatus comprising an absorber and an evaporator having upper and lower portions connected to form an inert gas circuit, a boiler connected to said absorber to form a solution circuit, means for liquefying refrigerant vapor produced in said boiler and for upper portion thereof, and means for circulating the inert gas through said evaporator under conditions such that the liquid refrigerant is propelled upwardly therethrough by the inert gas as it is evaporating into the inert gas.

4. Absorption refrigerating apparatus comprising an absorber and an evaporator having a pluralityof serially connected substantially horizontal portions connected to form an inert gas circuit, a boiler connected to said absorber to form a solution circuit, means for liquefying refrigerant vapor produced in said boiler and for supplying the same to the lower portion of said evaporator and a power driven pump for circulating the inert gas through said evaporator under conditions such that the liquid refrigerant is conveyed through said serially connected portions of said evaporator by the frictional drag of the inert gas flowing through saidevaporator.

ingan absorber and an evaporator including a rising conduit section connected to form an inert gas circuit, a boiler connected to said absorber to form a solution circuit, refrigerant vapor produced supplying the same to said evaporator below said rising conduit section, and a power driven circulator in said inert gas circuit arranged to blow the inert gas through said evaporator at a velocity such that the refrigerant liquid is swept into said rising conduit and is elevated therethrough by the inert gas.

6. Absorption refrigerating apparatus comprising an absorber and an evaporator connected to form an inert gas circuit, a boiler connected to said absorber to form a solution circuit, means forliquefying refrigerant vapor produced in said boiler and for supplying the same to said evaporator, means for circulating the inert gas in said boiler and for through said evaporator under conditions such t that the liquid refrigerant is propelled therethrough by the inert gas as it is'evaporating into the inert gas, and mean draining said evapoabove a predetermined level.

7. Absorption refrigerating apparatus comprising an absorber and an evaporator having upper and lower portions connected to form an inert gas circuit, a boiler connected to said absorber to form a solution circuit, on air cooled condenser extending to an elevation below the elevation-of the upper portion of said evaporator connected to receive refrigerant vapor from said boiler and to discharge refrigerant liquid by gravity into the lower portion of said evaporator,- and means for circulating the inert gas through said evaporator under conditions such that the liquid refrigerant is propelled upwardly therethrough by the inert gas as it is evaporating into the inert gas.

8. Absorption refrigerating apparatus comprising an absorber and an evaporator connected to form aninert gas circuit, a boiler connected to to said evaporator below the means for liquefying refrigerant accumulating therein refrigerant vapor is removed from vey the liquid refrigerant to all portions of said a continuous conduit.

9. Absorption refrigerating apparatus comprising an absorber and an evaporator connected to form an inert ga said absorber to form a solution circuit, means for liquefying refrigerant vapor produced in said boiler and for supplying the same to said evaporator, a circulator for the inert gas of the type in which the discharge pressure varies with the density and pressure of the inert gas for circulating the inert gas through said evaporator under conditions such that the liquid refrigerant is propelled therethrough by the inert gas as it is evaporating into the inert gas whereby the rate of inert gas circulation varies with changes in ambient temperature conditions to maintain the refrigerating capacity of the unit under varying conditions.

10. That improvement in the art ofabsorption refrigeration which includes the steps of circulating an absorbing solution between an absorbing zone in which refrigerant is added to the solution by contacting thesame with a mixture of a pressure equalizing medium and refrigerant vapor and a generating zone in which a refrigerant vapor is removed from the solution by the application of heat thereto, passing the vapor produced in the generating zone in heat exchange relationship with cooling air to convert the vapor to liquid, supplying the liquid to the bottom portion of an evaporating zone having portions of different slopes, circulating the pressure equalizing medium refrigerant vapor mixture through the evaporating zone with a velocity sufficient to propel the liquid through portions of the evaporating zone having a slight slope by the frictional drag exerted on a stream of the liquid by the pressure equalizing medium refrigerant vapor mixture flowing thereover and to propel the liquid through portions of said evaporating zone having a steep slope by the frictional drag of the pressure equalizing medium refrigerant vapor mixture flowing through a body of the liquid, and simultaneously evaporating'the liquid into the pressure equalizing medium refrigerant vapor mixture to produce refrigeration.

11. That improvement in the art of absorption refrigeration which includes the steps of circulating an absorbing solution between an absorbing zone in which refrigerant is added to.

the solution by contacting the same with a mixture 10: a pressure equalizing medium and refrigerant vaporand 'a generating zone in which the solution by the application of ,heat thereto, passing the vapor produced in the generating zone in heat exchange with cooling air to convert the vapor to liquid, supplying said liquid to an evaporating zone having an upstanding section, circulating the pressure equalizing medium refrigerant vapor mixture through the absorbing zone and through the evaporating zone under conditions such that the 'refrigerant is carried upwardly through the upstanding section of the e1vaporat-' ing zone byithe pressure equalizing medium recircuit, a boiler connected to frigerant vapor mixture passing through a body of the liquid in such section.

12. That improvement in the art of absorption refrigeration which includes-the steps of supplying a refrigerant liquid to an evaporating zone, propelling a pressure equalizing medium through the evaporating zone to sweep or drag the liquid refrigerant therethrough as it isevaporating to produce refrigeration; absorbing :the refrigerant vapor from the pressure equalizing medium in an absorbing zone, and regulating -the rate of, flow of the pressure equalizing medium through the evaporating zone by the variations in resistance to the flow of the pressure equalizing medium and the changes in density thereof eifected by changes in ambient temperature conditions.

13. Absorption refrigeration apparatus of the type utilizing an inert pressure equalizing medium including an anti-gravity evaporator comprising a fluid passageway having lower inlet and upper outlet openings at appreciably different elevations, means for'supplying liquid refrigerant to a lower portion of said passage .for

propulsion upwardly therethrough, means for supplying inert pressure equalizing medium to the inlet of said passageway under suflicient pressure and velocity to propel liquid refrigerant upwardly therewith as the refrigerant evaporates thereinto to=produce refrigeration, and in such manner that the inert medium passes into and out of the refrigerant as it flows along said passage.

14. A refrigerating system of the absorption type including an evaporator element having a gas and liquid passage, an absorber element having a gas and liquid passage, said absorber and said evaporator being connected to form an inert gas circuit, a generator, means for conveying absorbing liquid from said generator to said absorber passage and from said absorber passage to said generator, means for liquefying refrigerant vaporproduced in said generator and for supplying the liquid to said evaporator passage, and means for flowing the inert gas through one of said pasages under suflicient pressure and velocity to propel liquid-through said one passage in such manner that the liquid is nonuniformly distributed in said one passage and the inert gas passes into and out of the liquid in a portion of said passage in which the liquid is present in a relatively large quantity.

15. That method of producing a refrigerating effect with the aid of a refrigerating system involving a source of refrigerant vapor, a refrigerant -vapor liquefying means, an absorber, and.

an evaporating element having a passageway defining wall, which includes the steps of introducing refrigerant liquid into said passageway, circulating an inert gas through said passage-.

way with sufllcient pressure 'and velocity to 16; Absorption refrigerating apparatus comprising an absorber, an upstanding evaporator.

a generator, and an air-cooled condenser connected in circuit, said condenser beingarranged to receive refrigerant vapor from said generator, said condenser .being so positioned that a portion thereof is at an elevation belowthe upper portion of said evaporator, means for conveying with a velocity suiiicient Q refrigerant liquid from said'condenser to" said upstanding evaporator at an elevation below the upper end thereof, and means for propelling an inert gas' upwardly through at least the upper portionof said upstanding evaporatorwith sufficient pressure and velocity to drag evaporating refrigerant liquid upwardly in said evaporator whereby condensation of refrigerant vapor and evaporation of refrigerant liquid occur at least partially at the same elevation.

' l'lrAbsorption refrigerating apparatus comprising an upstanding evaporator, an-absorber, means connecting said evaporator and absorber for circulation of inert gas therebetween, a generator, a gas'lift pump for circulating absorption solution through a circuit including said absorber and said generator, means'for supplying pumping gas to said pump from the inert gas circulating between said absorber and said evaporator, a condenser connected to receive refrigerant vapor from said generator and to supply refrigerant liquid to evaporator below the top thereof, and means for placing the inert gas flowing through said evaporator under sufficient pressure to cause gas 25 to flow through said evaporator with a velocity sufficient to circulate refrigerant liquid upwardly therethrough against the pull of gravity by the frictional force applied to the liquid by the inert gas.

18 An evaporator adapted for use in an absorption refrigeration system of the type employing -a pressure equalizing medium comprising means forming a low temperature section, means forming a high temperature section, said low temperature section including a sinuous conduit having portions located at different elevations, means connecting one end of'said low' temperature section to one end of said high temperature section, means for supplying liquid refrigerant to said low temperature section, and means for passing pressure equalizing medium in contact with the surface of a body of the liquid refrigerant in such. manner' as to distribute said liquid refrigerant. through; said .low temperature section of said evaporator to produce refrigeration by the evaporation of said liquid into said pressure equalizing I 19. An evaporator as defined in the preceding claim characterized by the fact that said low and high temperature sections are located at different elevations. and one of said sections being pro- ,vigtoad with extended heat absorbing surfaces.

- .Anabso tion refrl eratin a aratu i d i rp 8 pp 8 n spaced substantially horizontal gas and liquid eluding a tubular evaporator, a tubular condenser positioned laterally of said evaporatona refrigerant liquid connection between thelowereportion of said condenser and the lower portion of said evaporator, means for conveying a mixture ofrefrigerant vapor and a pressure equalizing medium from" an-upper portion of said evaporator.

for supplying .pressure equalizing medium toithe lower portion of said evaporator, said tubular;v evaporator being so constructed and arranged that'said pressure equalizing medium 'flows 65 through saidevaporatorwith sufilcient lvelocity to propel the-.refrigerantliquid in the direction of gas flow and to form a. mixed column of refrigerant liquid and-pressure equalizing medium which column is disposed intermediate two bodies of liquid refrigerant'over the surface of which the pressure equalizinggmedium flows.-

,2l. An evaporator adapted'for ,use in anabsorption refrigeration system.offthetype employing an inert pressure equalizing medium, com-- pressure equalizing said upstanding prising a plurality of substantially, horizontally disposed tubular passageways having fluid conducting means connecting the same, certain of said horizontally disposed sections being located 5 at dlll'erent elevations, means supplying liquid refrigerant to a lower one of said sections, means for conveying a mixture of inert pressure equaliz ing medium and refrigerant vapor from an upper one of said sections, means for supplying an inert sections, said evaporator. being so constructed and arranged and said pressure equalizing medium flowing through said sections with sufficient velocity to cause liquid refrigerant from a lower one of said sections to form a mixed column of liquid and inert medium in said fluid conducting means and to distribute liquid refrigerant from a lower section through an upper section of. said evaporator.

20 22.Refrigerating apparatus comprising an inupwardly through said evaporator, said evaporator being soconstructed and arranged that the refrigerant liquid is circulated therethrdugh by the upwardly flowing inert gas.

I 23; Refrigerating apparatus 7 comprising an evaporatonan absorber, a boiler, a condenser,

means connecting said evaporator and said absorber to form therewith a pressure equalizing medium circuit, means connecting said absorber and said boiler to form therewith an absorption 40 solution circuit, means connecting 'saidboiler,

condenser and evaporator to form a liquid refrigerantfsupply means for said evaporator, said evaporator comprising a plurality of horizontal vertically spaced coil sections and asuperposed box-cooling section, riser conduits connecting ad- Jacent evaporator sections, and power-driven means for circulating fluid through said pressure equalizing medium circuit, said circuit being connected to cause fluids to, circulate upwardly through said evaporator, and said condenser being connected to the lowest of said coil sections.

24. Absorption refrigeratingi apparatus com-- prising a generator, a condenser, an absorber, an evaporator including a plurality of vertically passageway forming means, means providing for circulation of absorption solution between said absorber and said generator, means for supplying refrigerant vapor produced in said generator to said condenser, means for conveying refrigerant liquid from said condenserto-said evaporator,-

and means providing for circulation ofinert gas frigerant is circulated through said 'l'iorizontalpassageway forming meafis and upwardly between adjacent horizontal passageway forming means by the upwardly. flowing inert gas. i

,25." Absprption refrigerating apparatus comprising a generator, a condenser, an absorber and an evaporator, said evaporator including an elonated conduit formed into afpiurality of vertically spaced substantially horizontal sinuous conduit sections serially connected by upstanding conduit diumto a lower one of said sections, shelf elements adapted to support chilling receptacles overlying said sinuous conduit sections in heat conducting relationship therewith, means for conducting refrigerant, vapor from said generator to said condenser, means for conducting refrigerant liquid from said condenser to the lowest of said sinuous coil sections, and means for circulating inert gas between said absorber and said evaporator in a direction to flow upwardly through said conduit and with sufficient velocity and pressure todistribute theliquid refrigerant through said conduit, whereby the refrige'rant liquid is conveyed by the inert gas in an elongated path beneath said shelf elements as it is evaporating to produce a refrigerating effect.

26. Absorption refrigerating apparatus: coman evaporator, sa d evaporator including an elongated conduit formed into a plurality of vertically spaced substantially horizontal sinuous conduit prising a generator, a condenser, an absorber and 7 sections serially connected by upstanding conduit sections, shelf elements adapted to support chilling receptacles overlying said sinuous condull; sections in heat conducting relationship therewith, means for conducting refrigerant vapor from said generator to said condenser, means for conducting refrigerant liquid from said condenser to the lowest of said sinuous coil sections, means for circulating inert gas between said absorber and said evaporator in a direction to flow upwardly through said conduit and with sufllcient velocity and pressure to distribute the liquid refrigerant through said conduit, a casing enclosing said conduit and said shelf elements and arranged out of heat transfer relationship therewith,

whereby the refrigerant liquid is conveyed by the inert gas in an elongated path beneath said shelf element in heat transfer relationship therewithand out of heat transfer relationship with said casing as it is evaporating to produce a refrigerat-v ing effect. I

27. In a device of the character described, a cabinet structure having an insulated refrigerating chamber and a machinery compartment arranged for circulation of cooling air therethrough, an absorption'refrigerating apparatus associated with said cabinet including, an air cooled condenser in said machinery compartment, an evaporator in said refrigerating chamber, the upper portion of said condenser terminating below the top wall of said cabinet structure and the lower end of said condenser'e'xtending below the upper duits and said fluid conducting conduitsfsaid fluid conducting conduits being positioned in the rear part of said casing rearwardly of said receptacles,

means for supplying a refrigerant liquid to a lower one ofsaid evaporator conduits, and means for circulating a pressure equalizing medium through said evaporator conduits and fluid conducting conduits with sufilcient velocity and pressure to distribute the liquid refrigerant through said shelf-like coils and to convey the liquid refrigerant upwardly through said connecting conduits.'

29. Refrigerating apparatus ofthe type employing an inert pressure equalizing medium, comprising a plurality of substantially horizontal evaporator conduits arranged to form shelf-like coils and positioned in vertically spaced relationship, fluid conducting conduits serially connecting said horizontal conduits, shelf elements of heat conducting material overlying and concealingcertain of said shelf-like coils and adapted to support chilling receptacles'directly over said shelflike coils, a chilling unit housing positioned around said evaporator conduits, said fluid conduits and said shelf-elements and out of heat conductin relationship therewith, means for supplying a refrigerant liquid to a lower one of said evaporator conduits, and means for circulating a pressure equalizing medium through said-evaporator conduits and fluid conducting conduits with sufflcient velocity and pressure to distribute the liquid refrigerant through said shelf-like coils and to convey the liquid refrigerant upwardly through said connecting: conduits.

30. Refrigerating apparatus of the type employing an inert pressure equalizing medium, comprising a plurality of substantially horizontal evaporator conduits arranged to form shelf-like coils and positioned in vertically spaced'relationship, fluid conducting {conduits serially connecting said horizontal conduits, shelf-like plates ofheat conducting material supported on certain of said shelf-like coils and ,adapted to support portion of said evaporator, means for supplying refrigerant vapor to said condenser, means for conveying liquid refrigerant from said condenser 'to the lower portion-of said evaporatorlsaid evaporator including a plurality of horizontal portions positioned in vertically spaced relationship,

chilling receptacles overlying and in heat transfer relationship with said horizontal portions, and means for circulating an inert, gas through said evaporator in a manner to flow through each of said horizontal portions and thence upwardly to the next higher horizontal portion and to distri'lzoute theiliquid refrigerant through said evaporaor. v r28. Reg'frigerating' apparatus of the type employing an inert'pressure equalizing medium, comprising a plurality. of substantially horizontal evaportor conduits arranged toform shelf-like coils and positioned in vertically spaced relationship, fluid conducting conduits serially connecting said horizontal conduits, said horizontal conduits supporting and underlying chimngfreceptacles, a casing element enclosing said evaporator contion operable at a high'temperature, an absorber,.

means providing for circulation of absorption I solution between said generator and said absorber,

' means for conducting refrigerant vapor from said chilling receptacles directly over said shelf-like coils, a casing enclosing said coils, said fluid conveying conduits and said plates, said casing being attached to and supported by said plates, means for supplying a refrigerant liquid to a lower one generator to said condenser, means for conducting refrigerant liquid from'saidcondenser to said lowtemperature evaporator section-means for I conducting pressure equalizing medlumfrom said absorber to said low temperature evaporator section, means for conducting pressure. equalizing medium from said low temperature evaporator section to said high temperature evaporator section, means for conducting pressure equalizing medium from said high temperature evaporator section to said absorber, the construction and arrangement being such that the pressure equalizing medium distributes refrigerant liquid through said the liquid refrigerant low temperature section and conveys refrigerant liquid which passes through said low temperature section in the liquid state to said high temperature section, a casing enclosing 'said low temperature evaporator section and arranged out of heat conducting relationship with both of said evaporator sections.

32. Inan absorption refrigerating apparatus, a generator, a condenser, an evaporator including a substantially horizontal shelf-like low temperature coil section adapted to support and refrigerate a chilling receptacle and a high temperature air cooling section provided with an extended heat absorbing surface, an absorber, means providing for circulation of absorption solution between said generator and said absorber, means for conducting refrigerant vapor from said gen- I erator to. said condenser, meansior conducting refrigerant liquid from said condenser to said low temperature evaporator section, means for conducting pressure equalizing medium from said absorber to said low temperature evaporator section,

' means for conducting pressure equalizing medium from said low temperature section to said high temperature evaporator section, means for conducting pressure equalizing medium from said high temperature evaporator section to said absorber, the construction andarrangement being such that the pressure equalizing medium distributes refrigerant liquid through said low temperature section and conveys refrigerant liquid which passes through said low temperature section in the liquid state tosaid high temperature section, a casing enclosing said low temperature evaporator section and arranged out of heat conducting relationship with-both of said evaporator sections.

33. Absorption refrigerating apparatus com prising an absorption solution circuit including an absorber and a boiler, a pressure equalizing medium circuit including an evaporator and said absorber, means for supplying vapor generated in said boiler to said evaporator in liquid form, and means for propelling a pressure equalizing medium through said pressure equalizing medium circuit with a velocity such that foreign matter carried into I said evaporator is removed therefrom through said pressure equalizing medium circuit. 34. An evaporator adapted for use in absorp-' tion refrigerating systems of the type employing a volatile refrigerant, an absorbent for the refrigerant, and a gaseous pressure equalizing medium which is inert with respect to the refrigerant and absorbent, said evaporator comprising a vessel constructed and arranged to contain refrigerant liquid therein, means for conducting refrlgerant liquid to said vessel, means for introducing pressure equalizing medium into said vessel above the surface of refrigerant liquid freshly supplied to said vessel with sufficient velocity and pressure to propel liquid through said evaporator, and means for removing pressure equalizing medium, refrigerant vapor'and non-volatile foreign matter from said vessel at a level above the level at which said pressure equalizing medium introducing means is arranged to' introduce pressure equalizing medium into said vessel.

85. 'lhatimprovement'inthe art of producing- I 1 1 refrigeration by means of a refrigerating system of the type employing a refrigerant, an absorbent therefor and a gaseous medium inert with respect 1 to the refrigerant and the absorbent which includes the steps of evaporating the liquid refrigerant in an evaporating zone into the inert gas to produce refrigeration and removing unevaporated refrigerant and foreign material from the evaporating zone by flowing the inert gas. therethrough at a high velocity.

36. Absorption refrigerating apparatus com-Q prising an evaporator and an absorber connected to form an inert gas circuit, a boiler and said absorber connected to form a solution circuit,

means for supplying refrigerant vapor produced in said boiler to said evaporator. in liquid phase,

said evaporator comprising a continuous passageway having a liquid refrigerant connection to said liquid refrigerant supply means and inert gas connections to said inert gas circuit, and

means for circulating an inert gas through said inert gas circuit with a velocity sufiicient to convey the liquid refrigerant and foreign material finding its way into said evaporator through said evaporator and to direct unevaporated. liquid refrigerant and foreign material such as absorption -solution fromsaid evaporator into said solution circuit through a portion of said inert gas circuit.

37. An evaporator for use in three-fluidabsorption refrigerating systems comprising means forming a pluralityof vertically spaced serially connected substantially horizontal passageways adapted to underlie and refrigerate ice trays, liquid refrigerant supply means arranged to supply P liquid refrigerant to the lowest of said passageway forming means, inert gas supply means arranged to supply inert gas to the lowest of said passageway forming means above the surface of the liquid refrigerant therein and with sumcient velocity and pressure to propel liquid through said passageway, and inert gas and refrigerant vapor removal means connected to the highest of said serially connected passageway forming means.

'38. An absorption refrigeration apparatus of the pressure equalized type including an evapo-' rator element in which a transfer of refrigerant vapor occurs between a refrigerant liquid and an inert pressure equalizing element in which a transfer of refrigerant vapor occurs between an absorbing liquid and said inert pressure equalizing medium, means for producing refrigerant liquid and for supplying refrigerant liquid to said evaporator element,

means for supplying absorption liquid to said absorber element, means for flowing pressure equalizing medium into one of said elements above the surface ,of the liquid supplied thereto and for passing the pressure equalizing medium through said one element with sufficient force to distribute the liquid supplied to said one element non-uniformly through said one element as a transfer of refrigerant vapor is occurring between the distributed liquid and said inert pressure equalizing medium.

i CURTIS C. OOONS.

WILLIAM H. KITTO.

medium, an absorber 

